Essential hypertension is a major public health problem. As such, an extensive literature has developed concerning its etiology and development. The data have consistently implicated psychosocial factors, most notably problems in the expression of anger and hostility; yet, conceptual and methodological problems have left many unanswered questions. The principal purpose of the proposed project is to examine two hypotheses that bear on this issue: (a) the critical psychosocial dimension in hypertension is not an intrapsychic conflict, but is a specific, measurable deficit in assertiveness; and (b) psychosocial factors (i.e., assertiveness deficits) are of significance primarily among hypertensives who show evidence of increased autonomic activity. Two studies will be conducted to examine these hypotheses. In one, three borderline hypertensive groups which differ in extent of suspected autonomic involvement (as marked by plasma renin levels, in conjunction with other indices sensitive to sympathetic nervous system activity), normotensive individuals with ulcerative colitis, and normotensives without a chronic illness will be compared on a variety of behavioral, self-report, and "significant other" measures of assertiveness and anger. A second study will compare young adults who have a hypertensive parent with a matched group having normotensive parents on a similar battery of measures. In both studies, individual differences in behaviorally-induced cardiovascular reactivity will be assessed, and examined in relation to assertiveness deficits. The second study will also examine the combined influences of parental hypertension and individual differences also examine the combined influences of parental hypertension and individual differences in stress-related physiologic reactivity on resting blood pressure measurements. The results will have implications for our understanding of the nature of essential hypertension and may point to a new strategy for treatment (i.e., social skills training).